Rotating dynamoelectric machines, such as motors and generators (hereinafter motors), have a tendency to build heat up internally during operation. One of the many techniques used to reduce this heat build-up is the circulation of air within the housing or shell thereof and past the windings wherein the heat is generated. In some designs, the rotor carries a plurality of end blades, typically die cast, which propel the air much as a fan propels the air as it is turned. Also in the prior art, there are many designs for baffles, shrouds, and the like for directing the flow of air from a series of ventilating holes in the shell, past the blades, through the windings, and out the other end of the motor. Many different designs are utilized in the prior art in order to accommodate many different air paths as might be considered desirable by the designer. However, these baffles, deflectors and the like can be constructed of multiple pieces, some of which are rotating and others of which are stationary in order to maximize the effect of the rotating blades in drawing cooling air through the shell.
As motors are generally available from a wide variety of manufacturers, and these many different devices are sometimes considered to be functionally equivalent, the cost thereof can be a significant factor in the selection of one competitor's device over another's. Therefore, there has been significant attention paid to many of the various design details, including both motors and generators, over the years.
To solve the problems associated with multi-piece deflectors, including not only the required close manufacturing tolerances of those designs as well as the increased cost thereof in both the manufacture and installation thereof, the inventors herein have succeeded in designing and developing a one-piece, integrally formed, plastic air deflector which can be conveniently mounted to an end bracket of a motor by a mounting ring. The one-piece, integral, plastic construction of the deflector greatly reduces the cost not only of the piece part, but also minimizes installation cost as the deflector is mounted with four screws into an end bracket for the motor. In addition to a generally annularly shaped mounting ring, the deflector includes an axially displaced generally annularly shaped shroud with four webs extending between the inner circumference of the shroud and the outer circumference of the mounting ring. The deflector is oriented within the shell to be adjacent the holes therein through which cooling air passes.
As the webs occupy very little of the space between the shroud and the mounting ring, little interference or blockage of air flow is caused. Thus, cooling air readily flows through the ventilating holes, through the deflector by flowing past the stationary webs, and the air is then drawn into the central portion of the motor by rotating rotor blades which fit and rotate closely against the shroud portion of the deflector. The shroud not only fits closely against the rotor blades, but extends substantially to the inner circumference of the shell, with four notches therethrough for insertion of the thru-bolts which join the end brackets to the shell, as known in the art. This positioning of the shroud prevents re-circulation of the air around the blades which would interfere with the cooling action of the air as it circulates through the motor.
While the major advantages and features of the present invention have been described above, a more complete and thorough understanding of the invention may be attained by referring to the drawings and description of the preferred embodiment which follow.